Method and instrument for surveying



Jan. 30, 1923.

SI SMITH. METHOD AND INSTRUMENT FOR SURVEYING.

.27 wit Ooan 30 In the accompanyingdrawing,

Patented Jan. 30, 1923.

PATENT OFFICE.

TROW S. SMITH, OF, CHICAGO, ILLINOIS. I

i METHOD A ND'INSTRUMENT FOR SURVEYING.

Application filed January 17, 1919. Serial 110. 271,586.

To all whom it may concern Be itknown'that I, .Tnow S. SMITH, a citizen of the United States, residing at 5715 Race Avenue Chicago, Cook County,

-Illinois, have invented-certain new and useful Improvements in Methods and Instruments for Surveying, of which the following is a specification.

This invention relates more particularly 10 to a new method and new apparatus for topographlcal surveying, although, of course,

it may'have a more general application to traverses of all kinds.

The principal object of the invention is to provide means for simplifying and expediting the work in' topographical surveyingby' eliminating the StLCllft correctlons WhlCh' have heretofore been necessary in traverses of this kind, and in the accomplishment of these .desired'results, the in- I vention includes the provision of a new form of stadia rod and also the provision ofvertical stadia lines in the telescope. The invention, therefore, consists in the new 2 5' method and in theapparatus for carrying out theoperation of this new method of.

surveying, and to the novel construction, combinatlon and arrangement of the parts 1n the apparatus.

' Fig. lis a view representing a telescope,

and a horizontal stadia rod as employed in I carrying out this invention;

rod in folded position. i i

v Fig. 4 is anenlarged perspective of a portion ofthe' stadia rod in operative posi- 40Iti0n. i r V '5 is a detail view showlng a sight Fig. plate with a slit in it ;';and

Figifi is a vlew showing of center and stadia lines in a telescope.

stadia' measurements is based on the geometrical principle that the lengths of par- 7 allel lines subtending an angle are proportionate to their distance from the apex of that angle'yand in practice, the intervals {between the stadia wires are frequently ar- Fig. 2 is a viewof a portion of the stadia 35 rod. i o v p *Fig. 3 is a view of a portion of the stadia the arrangement In surveying, the theory of the method of tion, asshown in Fig. 2, 1n WhIClI 'POSIJbIOII they-are held by means Y of the inclined may beaus'ed in non. Y

rangedso that at a distance of 100 feet ai space of one foot hall be intercepted on the rod. This is true, however onlyifor horizontal sights, and when the stadiarod is held on an elevation, or in a 'depressionya correction must be made, asthe stadia wires for; obtaining come these difficulties by, Providingvertical.

stadia wires in the telescope or transit'in addition to the horizontal and vertical center lines, and in addition-tohorizontal stadia position at a fixed height and at right angles tothe line of sight.

Referring, now, more particularly to the or line will intercept a length on the rod greater than-the slope distance, and correction tablesare commonly used the correct distances.

Thepresent invention proposes to over "lines; and also by providing a stadia rod which can be maintained in ahoriz'ontal drawing, numeral 1 designates, generally,

a telescope of a urveyors'instrumentwhich is "mounted upon a tripod 2 orany suitable support, and in the telescope there is provided a diaphragm, as represented in Fig.

6,- upon which there is usually a vertical center line 3 and a horizontal center line 4.

Horizontal stadialines may also be provided, but: the present invention: contemplates as a distinct improvement the pro vision of vertical stadia lines 6,'in addition the'same or any -well known character. Supplementing the telescope with-these vertical stadia lines 6 i an-improved levelto the others previously 'mentioned, and of v ingor 'stadiarod which'comprises a sup-''''' the bar and it support with a nut 10 for spring washer 11 which permits a relative rotation of the parts to a right angledposlthe ordinary, vertical posi drawing the bolt uptightly against the The upper end of the support 7 is formed with a slot 13 and with'a recess 14 on the side adjacent the bar 8;. n the side of the support 7, opposite the bar 8, is a plate 15 in which is a narrow sight slit 16. Mounted in therecess le is ayhinged frame, one part 17 of which is pivoted to swing outwardly from the end of the support- 7v and other part 18 which i hinged at the outer end of the first part 17 and carries a hair or wire 19 which is disposed parallel to. the slit 16 of the plate 15. As shown by Fig. 3, this hinged frame 17, :18, can be. folded-into the recess 14: and this i the position which it occupies when the support '7 is folded parallel to the bar 8, so that the frame and -the hairline which it carries will be protected when not in use. It is obvious that the outer portion 18 of this framecan' be moved up and down in front of the support 7 to sight from a depression-or from an elevation through the sight slot 16 with respect tothe hair-line 19. r a

Attached to the bar 8- is a level 20 for determining when the bar is in ahorizontal position. It isto beunder'stood, of course, that the support 7 and the bar 8 may be connect'ed'to each other in any desired or suit 7 able manner, either: temporarily or'- permanently, but it is necessary that the bar 8 be suppo'rted in a horizontal position and'at right angles to the line ofsight from the I telescope 1. i

It has been foundinpractice that heat w'aves have practically no, effect for distances above four feet, and therefore it is .'contemplated thatthe' bar 8. shall be supported in, a horizontal position at a height Furthermore even if there were strata of heat, a horizontallydisposed bar would'beiin the same stratum, andtherefforenot subject to the error caused by different strata: of heat or heat waves. v

Itis understood, furthermore, that instead of: the specific open sight attachment which is shown in conn-ection with the 'stadia' rod, any other suitable-sight device such asfa tel'escope' might be provided at the. center I of the rod-, as the object of thesighta-ttach- ,ment is to position the ends-of the horizontal barf8gso that they will be, exactly at right angles to the; line of Sight flOln the 't'elev scope 1;" If desired, the bar'8 may also. be mounted upon a tripod, with'or without a .telescjope these refinements merely conductogreateraccuracy.- 4 i a 'Inoperation,thetelescope is placed, in

,"posi't'ionzas"-.desired,and the stadia rod is 'place'd at a distance therefrom either onan -elevatiorior depression-, or ,upon' level on the stadia rod, directly toward the telescope, and at this time the arms of the bar 8 will therefore he at right angles to the line of sight from the'telescope. The gradnations on the horizontal bar 8 are then observed through the telescope and noted, and the distance between thestadia rod and the telescope is then determined by the stadia measurements. No corrections are necessary for theinclination' of the stadia rod to the line of sight as this inaccuracy is eliminated. s. v

'Tliis method and apparatus may also be used to advantage even in level country where it is diflicult to see the lower end of a vertical stadia rod because of bushes, shrubs or the like, or, as noted above, where there 23 of heat waves. I a

It is obvious that various changes'can ,is any dan er of error due to'the presence be made in the construction'of the apparatus without departing fromthe spirit and scope of the invention, and still embody the method oi operation herein disclosed.

I claim: 1. In apparatusofthevclass-described, a stadia rod comprising a graduated bar, a

support for holding the bar, in a horizontal position, means for leveling the harm the horizontalposition, and sighting means on. said a support substantially at the longitudinal center of saidbar for'positioning the horizontal bar at right angles to the line of sight. i a

2.111 a surveyors stadia rod, a graduated bar, a support therefor to hold the bar in horizontal position, means. for leveling the bar in the horizontal position, and sighting means in connection with the-support intermediate the ends of the barfor positions ing the bar at right angles to the line of sight; Y I

3. In a surveyors levelingv or stadiarod,

a graduated bar, a support, therefor foldable against the bar, and a sighting attachment;

on the supportat the longitudinal center of thenbar for positioning the bar .at right angles to the line of sight determined by said attachment 7 4. In a. surveyors stadia bar, a support forholding the bar in horizontal position, foldab'le agairjist the'bar,

and means on the support for positioning the bar at right anglesto' the. line ofsight,

rod, a graduated.

said means comprising a member having a vertically disposed. slit and .a hairline frame movable in front of the slit.

5: Ina surveyors-stadia rod, a graduated bar, a support for holding the bar in horizontal position, foldableiagainst the bar, a

member inconnection with the support} having a vertical slit when-the support is in upright position, and a;hai-rline supporting frame movable against the support when-the latter-is in folded position; and adaptedv to be extended in; frontof-;the-= said slit-.with

the hairline of the frame at various horiand fold-able forwardly with a Wire diszontal angles in front of the slit. posed parallel to the slit and adjustable at 6. In a Surveyofs staclia rod, a graduated various horizontal angles with respect to the 10 bar, a support for the bar foldable parallel slit.

1 with it and having a recess and a slit adja- January 13, 1918.

cent the folding point, double hinged frame carried by the support in the said recess TROW S. SMITH. 

